ONE SUNDAY AFTERNOON in 1966, when Pink Floyd and the improvised-music group AMM were sharing a bill at the Marquee Club in London, AMM’s Keith Rowe laid his guitar flat on a table and dropped various objects onto it, eliciting an array of radically dissociated sounds. The Pollock-inspired technique fascinated Syd Barrett, Floyd’s guitarist. An early example of rock communing with true experimentalism, this episode may have just been a case of one former art student relating to anothereven though at the time British art schools tended to attract aspiring rock musicians rather than insurrection-minded instrumentalists.

All that changed when Roxy Music’s commercially viable symbiosis of pop and avant-garde redefined art school rock in the early 1970s, and a new generation was swept up in the subsequent punk revolution, armed with Brian Eno’s promise of the nonmusician as the